Nozzle for the expansion of hot liquids



Nov. 5, 1935. V I H. B. REITLINGER 2,019,694

NOZZLE FOR THE EXPANSION OF HOT LIQUIDS Filed March 16, 19:55

[227/222 Zor Patented Nov. 5, 1935 PATENT OFFICE.

NOZZLE FOR THE EXPANSION OF HOT LIQUIDS Henri B. Reitlinger, Paris,France, assignor to Oflce National des Recherches Scicntiflques etIndnstrielles et des Inventions,

Bellevuc,

France, and Camille Husson, Paris, France Application March 16, 1933,Serial No. 661,161 In Belgium March 19, 1932 6 Claims.

the temperature concerned.

t after the expansion and having acquired the The object of my inventionis to provide a nozzle capable of so mastering the explosion thatnaturally occurs, whenever a liquid placed under such conditions oftemperature and pressure is allowed to expand into a medium at lowpressure, that said liquid, partly converted into vapor highestpractically attainable velocity, flows out from the nozzle into the lowpressure medium in the form of a stable jet with parallel orsubstantially parallel stream lines. In other words, the object of myinvention is to convert the highest possible percentage of the energyavailable in the hot liquid under pressure into kinetic energy, whichcan be utilized for actuating a turbine or any jet apparatus, such as aninjector, an ejector, or the like.

For this purpose, the nozzle according to my invention is of a specialshape, including a converging inlet portion and a diverging outletportion, and the profile of the inner surface of said diverging portionclose to the point where it is joined to the profile of the convergingportion is curved, having its concavity turned toward the inside of thenozzle.

Other features of my invention will be hereinafter more specificallydescribed.

A preferred embodiment of the invention will now be described withreference to the accompanying drawing, given merely by way of example,and which is an axial sectional view of a nozzle for the expansion ofhot water under pressure.

The problem with which my invention is concerned is to expand hot water(or another liquid) at a pressure higher than the boiling pressurethereof that corresponds to its actual temperature with a view toobtaining motive power. For this purpose, I cause said water to expandprogressively and without shock from its initial to the desired lowpressure by allowing it to flow and take up velocity inside at least onenozzle according to the present invention, so as to convert the thermalenergy initially available in said water into kinetic energy. It is thenpossible to utilize the kinetic energy of the fluid issuing from thenozzle for actuating a turbine or for any other purpose.

The nozzle according to the present invention consists of a convergingportion, or duct, a directly joined with a diverging portion b of ashape analogous to that of an elongated tulip, the whole being sodevised that the expansion of water will take place in two phases, asfollows:

A first phase which corresponds to the flow of 5 the liquid through theconverging portion, from the medium under high pressure to the throat ofthe nozzle, and during which water flows with out evaporation, inaccordance with the laws of hydrodynamics;

A second phase which corresponds to the flow of the fluid through thediverging portion, from the throat (line A-B) of the nozzle into themedium at low pressure and during which a partial evaporation of watertakes place, this evapora- 15 tion necessitating, as soon as it starts,that is to say from the throat of the nozzle, a sudden increase of thesection of flow afforded to the fluid.

Concerning more particularly the shape to be :0 given to the divergingportion b, said shape is determined (in accordance with the laws ofthermodynamics, since the evolving fluid is a heterogeneous mixture ofliquid and vapor the temperature and specific moisture of which vary 25from point to point) so as to obtain a predetermined law of variation ofthe velocity along the axis of the nozzle. The cross section of thenozzle is thus calculated point by point, as a function of thetemperature, the specific moisture of 80 the mixture, the specificvolume thereof, and the velocity, for successive points of the axis ofthe nozzle.

I consider that it is advantageous to choose, as the law of variationsof the velocity along the 5 axis of the nozzle, a law of uniformacceleration. In this case, divergent portion b starts from the throatof the nozzle in the form of a surface substantially at right angles tothe axis of the nozzle and its profile may present a point of inflection40 between the throat and the outlet end of said portion b.

As for the outline or profile to be given to the converging portion a,it is determined, in accordance with the laws of hydrodynamics, so as toobtain a variation of the velocity along the axis that corresponds tothe law that has been chosen. Of course, account should be taken of thethermodynamic phenomena that determine the point at which vaporizing ofthe liquid is to begin and 50 therefore at which the converging portion0 stops so as to be angularly joined to the diverging portion b.

For the sake of cleamess I have assumed that the diverging portion ofthe nozzle is a body 55 of revolution. This is not at all a necessaryfeature of my invention and said portion of the .-nozzle may be givenany desired cross section,

polygonal or other, and the center line may be curved as well asrectilinear.

Because of the special shape of the nozzle according to rm; invention,it is possible to utilize the maximum of the energy available in theexpension of hot Water under pressure, whereas, up to now, nosatisfactory industrial results had ever been obtained, because use wasmade of nozzles having a profile substantially continuous (that is tosay without an angular point). Such nozzles do not provide a suddenincrease of the cross section at the point where a partial evaporationof the liquid begins to take place. Consequently the liquid cannotexpand down to the pressure of the low pressure medium, so that whenentering into this medium, the liquid explodes therein.

On the contrary, the nozzle according to the present invention makes itpossible to bring the fluid gradually and without shock down to thepressure of the final medium and therefore to obtain, at the outlet ofthe nozzle, a jet having stream lines that are very substantially andeven nearly rigorously parallel so that the whole of the energy that canbe supplied by such an expansion (within excellent limits of practicalefficiency) is accumulated in that expanded fluid.

- It will be readily understood that the nozzle according to the presentinvention renders it possible to obtain mechanical energy from heatedfluids at relatively low temperatures with a fairly good coeflicient ofefliciency, a system which could not be obtained with systems making useonly of steam.

While I have described what I deem to be a practical and efficientembodiment of the present invention, it should be well understood that Ido not wish to be limited thereto as there might be changes made in thearrangement, disposition and form of the parts without departing fromthe principle of the present invention as comprehended within the scopeof the appended claims.

What I claim is:

1. A nozzle for the shockless expansion of a hot liquid at a pressurehigher than the boiling pressure thereof that corresponds to thetemperature of said liquid, which comprises, a converging inlet part anda diverging outlet part directly joined with each other, the inner endof the profile of said diverging part being curved, with its concavityturned toward the inside of the nozzle, and

starting substantially at right angles to the center line of the nozzleat the point where it is joined to the profile of the converging part.

2. A nozzle for the shockless expansion of a hot liquid at a pressurehigher than the boiling 6 pressure thereof that corresponds to thetemperature of said liquid, which comprises, a converging inlet part anda diverging outlet part directly joined with each other, the portions ofsaid parts where they are joined to each other be- 10 ing curved, andtheir respective tangents being substantially at right angles to eachother, the inner end of the profile of said diverging part, adjoiningthe place where the parts are joined. being curved, with its concavityturned toward 15 the inside of the nozzle.

3. A nozzle for the shockless expansion of a hot liquid at a pressurehigher than the boiling pressure thereof that corresponds to thetemperature of said liquid, which comprises, a con- 20 verging inletpart and a diverging outlet part directly joined to each other, theportions of said parts where they are joined to each other being curved,and their respective tangents being substantially at right angles toeach other and the 26 tangent to the diverging part at the place wherethe parts are joined being substantially at right angles to the centerline of the nozzle, the inner end of the profile of said diverging part,adjoining this place of joining, being curved, with its 30 concavityturned toward the inside of the nozzle.

4. A nozzle for the shockless expansion of a hot liquid at a pressurehigher than the boiling pressure thereof that corresponds to the temper-35 ature of said liquid, which comprises, a'curved converging inlet partand a curved diverging outlet part directly joined to each other, theprofiles of said parts being joined to each other where they are curvedin opposite directions re- 40 spectively, and where the tangent to theprofile of the diverging part is substantially at right angles to thecenter line of the nozzle, the concavity of the portion of saiddiverging part adjoining the place where the parts are joined be- 45 ingturned toward the inside of the nozzle.

5. A nozzle according to claim 3 in which the inner surface of thenozzle is a surface of revolution.

6. A nozzle according to claim 4 in which the IQ inner surface of thenozzle is a surface of revolution.

HENRI B. REITLINGER

